There is considerable evidence that Hume thinks the moral sentiments (approval and disapproval) move us to action, at least in some circumstances. For one thing, he relies on the premise that moral evaluations move us to action to argue that moral evaluations are not derived from reason alone, in his most famous anti-rationalist argument. Presumably, this capacity of moral evaluations can be explained by the fact that (as Hume sees it) such evaluations are, or are the product of, moral sentiments. But this raises three interconnected interpretive questions. First, on Hume's account, much virtuous behavior is traceable to motives other than the sentiments of approval and disapproval; so when and how do the moral ..